Air handling units: what are they and how to install them?

What we know as air conditioners in air conditioning systems is what we call air handling units in ventilation, whose acronyms can be UTA or AHU, coming from the English term Air Handling Unit. In reality, these UTA are the main part of the air conditioning systems that require greater control. And these units do not take care of producing heat or cold air.

Because air handling units have the function of managing heat or cold, not producing it. They will receive, through external means - such as boilers or refrigerators, water pipes, or even through a refrigerant gas - the heat or cold previously produced. The UTA will then be responsible for managing these thermal sensations in order to distribute them to the rooms.

In other words, air handling units will take into account a series of variables to manage the air introduced into a room and offer the sensations that are selected in the air conditioner, either manually or automatically.

Independently, the UTA will manage:

• The arrival of outside air, to ensure good ventilation.
• By incorporating air filters into the air conditioning systems, the UTA will monitor the quality of the air they introduce.
• They must measure the temperature to make use of the heating or cooling systems, thus respecting the thermal sensation that the user desires.
• If there is more or less humidity, the UTA must adapt to this to continue providing the expected home comfort.

Normally, the air control units - called air conditioners - are used in places where specific regulation of climatic conditions is needed. For example, in very spacious places or where there may be many people.

• The UTA are used to provide air and ventilation to air-conditioned places through equipment that produces heat, but not ventilation air. For example, if the thermal solution is radiators, the UTA can provide the necessary ventilation air.
• In large auditoriums, concert areas, pavilions, or other areas with a high density of people, it is important to centralize the air conditioning system. In these cases, air control units will be very helpful.
• When it requires very high health conditions, as is usually the case in laboratories or hospitals - especially in operating rooms - these units can do a good job of rationalizing the supplied air.

The UTA units have an electromechanical part, which is the fan that will generate the necessary flow and static pressure. It will distribute the air throughout the room.

Installation of air handling units

To identify the places where we should install our air handling units, first of all we must understand the differences between the two main models. Nevertheless, the intention will be that these systems do not occupy space or take up a place in our homes:

1. Compact UTA units. In these cases, which are simpler and also more economical, we find air handling units formed by a single module that includes the different stages to treat the air. We can find models that can be installed outside the room to be ventilated, or also other narrow ones that can be mounted in a false ceiling. That is always provided that maintenance tasks can be enabled, although it is an option to have the unit visually hidden.
2. Modular UTA units. Compact systems are less common than modular UTA units, which are already quite large. In these cases, the installation is quite different, as they do not fit behind a false ceiling. A good installation place is on the roof of the building. Or even in a specific place that has direct ventilation from the outside. In these cases, air extraction and intake must be guaranteed.

On the other hand, it is worth noting that air handling units can be considered energy efficient. For example, they are capable of regulating their ventilation flow according to the carbon dioxide detected in the environment.

Similarly, it will be possible to regulate the flow variably according to the heat or cold conditions. This makes it necessary to use frequency converters in the fans, which are capable of adapting to one flow or another. The UTA units can also use cold air from the outside without the need to heat or cool it as long as it is detected that it is not necessary in the room to be conditioned. This is thanks to their capabilities to measure what is needed in each specific case. The air handling units can even recover some of the energy from the warm air they expel to the outside.